package test;
import java.util.Arrays;
public class Demo {
    public static void main(String[] args) {
    StringBuffer a=new StringBuffer("A");
    StringBuffer b =new StringBuffer("B");
    operate(a,b);
    System.out.println(a+" "+b);

    }
    public  static void operate(StringBuffer x,StringBuffer y){
        x.append(y);
        y=x;
    }
}